UDZ Venting Instructions

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CP-UBZ-UDZ-VENT (02-21) 1034632-0
GENERAL INFORMATION—CONTINUED
Venting and Combustion Air Requirements—Continued
⚠ CAUTION ⚠
• When an existing appliance is removed or replaced in a venting system, verify that the venting
system is properly sized to vent the new appliance. An improperly sized venting system may
result in the formation of condensate, leakage, and/or spillage.
• Do not intermix different vent system parts from different manufacturers in the same venting
system.
• Concentric horizontal and vertical vent/combustion air systems are the only venting/combustion
air systems approved for these units.
• Unit sizes 030–400 of model UBZ units and 150–400 of model UDZ units are certified only for commercial/industrial
installations.
• Unit sizes 030–125 of model UDZ units are certified for both residential and commercial/industrial installations.
NOTE: The unique concentric adapter assembly required with this heater allows for both combus-
tion air and exhaust piping with only one horizontal or vertical penetration hole in the building.
Hazards of Chlorine
The presence of chlorine vapors in the combustion air of gas-fired heating equipment presents a potential corrosion
hazard. Chlorine—usually in the form of Freon or degreaser vapors—when exposed to flame will precipitate from
the compound and go into solution with any condensation present in the heat exchanger or associated parts. The
result is hydrochloric acid, which readily attacks all metals including 300 grade stainless steel. Care should be taken
to separate these vapors from the combustion process. This may be done by the wise location of the combustion
air terminal with regard to exhausters or prevailing wind directions. Chlorine is heavier than air. Keep these facts in
mind when determining the installation location of the heater in relation to building exhaust systems.
Type of Pipe
All pipe is field-supplied. Select the installation type that applies, Requirements are listed for both the vent pipe and
the combustion air inlet pipe:
Residential installations:
• Single-wall vent pipe approved to UL standard 1738 for a category III appliance is required.
• Horizontal vent: the horizontal section of pipe in the vent terminal that extends through the box and runs concentric
through the combustion air pipe must be one-piece with no joints.
• Vertical vent: the section of pipe in the vent terminal that extends through the box and runs concentric through
the combustion air pipe must be one-piece with no joints.
• Combustion air inlet pipe: sealed, single-wall galvanized pipe is recommended for the inlet air run and terminal
combustion air pipe.
Commercial/industrial installations:
• Single-wall vent pipe approved for a category III appliance or single-wall, 26-gauge or heavier galvanized or
equivalent vent pipe is required between the heater and the concentric adapter box.
• Horizontal vent: the horizontal section of pipe in the vent terminal that extends through the box and runs concentric
through the combustion air pipe must be one-piece with no joints.
• Vertical vent: double-wall (type B) vent pipe is required for the vertical vent terminal. The section of pipe in the
vent terminal that extends through the box and runs concentric through the combustion air pipe must be one-piece
with no joints.
• Combustion air inlet pipe: sealed, single-wall galvanized pipe is recommended for the inlet air run and terminal
combustion air pipe.